During daily life, people always heat liquid (for example, water) to achieve various objectives. For example, during cooking, water is heated to be boiling so as to blanch food, or water is heated to generate vapor to steam food. During manufacturing of distilled water, water is heated to generate vapour, and the vapor is then condensed into distilled water. During power generation, water is heated to generate vapour, so as to push a turbine to generate electricity.
In the above examples, the vapor generated during heating still contains a large amount of heat, especially latent heat absorbed during vaporation. Among common liquids, water has the highest latent heat of vaporation being up to 2250 KJ/Kg. People have been trying to recycle or utilize heat energy in vapour. For example, Chinese Patent Application No. 200810081952.5 discloses a “high-efficiency energy-saving steamer” which may recycle the heat energy of the steam generated during steaming with “high-temperature high-pressure refrigerant” through “multi-source heat pump”. However, such disclosure is subjected to the following shortcomings:
1. The “high-temperature high-pressure refrigerant” compressor is limited to high pressure operation which gives a high energy consuming process with poor recycling efficiency and the compressor is fragile to wearing.
2. The “high-temperature high-pressure refrigerant” is expensive and poses harmful threat to the environment.
3. The multi-source heat pump” for heat absorption is bulky and not suitable for household applications.